[PATCH] REST: don't 500 if we get a non-int ID in /comment/ views

[Stephen Finucane]

On Sat, 2021-08-21 at 01:32 +1000, Daniel Axtens wrote:
> The Patch and Cover comment views passed unsanitised patch_id/pk
> down to the query set filter, which attempts to convert them to
> integers, fails, and propagates a ValueError up to us.
> 
> Rather than propagating it to the user as a 500, catch it explicitly
> and return a 404. Ideally we'd like to return a 400 and some explanation,
> but I can't see an easy way to bend Django or DRF to my will here.
> 
> Signed-off-by: Daniel Axtens <dja at axtens.net>
> 
> ---
> 
> Will need some tweaking for 2.2, but conceptually simple.
> 
> Stephen, would be interested if you can come up with a better way
> to propagate a meaningful error out to the user!

I did indeed find another way to do this. Two ways, in fact. I've submitted a
patch to do both, but tl;dr:

   A. We can use path converters (of type 'int') to ensure these requests never
      even hit our handlers
   B. We can use 'rest_framework.generic.get_object_or_404' instead of Django's
      own implementation, since the former also handles TypeErrors

Let me know if this works for you. I can apply it and cut a new release early
next week if you can't.

Cheers,
Stephen